5 Moose::Manual::Delta - Important Changes in Moose
9 This documents any important or noteworthy changes in Moose, with a
10 focus on backwards. This does duplicate data from the F<Changes> file,
11 but aims to provide more details and when possible workarounds.
13 Besides helping keep up with changes, you can also use this document
14 for finding the lowest version of Moose that supported a given
15 feature. If you encounter a problem and have a solution but don't see
16 it documented here, or think we missed an important feature, please
19 =head1 Version 0.89_02
25 =item New Native delegation methods from L<List::Util> and L<List::MoreUtils>
27 In particular, we now have C<reduce>, C<shuffle>, C<uniq>, and C<natatime>.
29 =item The Moose::Exporter with_caller feature is now deprecated
31 Use C<with_meta> instead. The C<with_caller> option will start warning in a
34 =item Moose now warns if you call C<make_immutable> for a class with mutable ancestors
36 This is dangerous because modifying a class after a subclass has been
37 immutabilized will lead to incorrect results in the subclass, due to inlining,
38 caching, etc. This occasionally happens accidentally, when a class loads one
39 of its subclasses in the middle of its class definition, so pointing out that
40 this may cause issues should be helpful. Metaclasses (classes that inherit
41 from L<Class::MOP::Object>) are currently exempt from this check, since at the
42 moment we aren't very consistent about which metaclasses we immutabilize.
43 Anonymous classes are also exempt, since they are often created automatically,
44 and the user is never given a choice about whether or not to make them
45 immutable. If you're sure you know what you're doing, you also can pass the
46 C<allow_mutable_ancestors> option to make_immutable to silence the warning
47 (but be aware that modifying those mutable ancestors can still lead to
48 incorrect behavior in your subclass).
50 =item Added Native delegation for Code refs
52 See L<Moose::Meta::Attribute::Native::Trait::Code> for details.
57 =head1 Version 0.89_01
59 L<Moose::Meta::Attribute::Native> has been moved into the Moose core from
60 L<MooseX::AttributeHelpers>. Major changes include:
64 =item C<traits>, not C<metaclass>
66 Method providers are only available via traits.
68 =item C<handles>, not C<provides> or C<curries>
70 The C<provides> syntax was like core Moose C<< handles => HASHREF >>
71 syntax, but with the keys and values reversed. This was confusing,
72 and AttributeHelpers now uses C<< handles => HASHREF >> in a way that
73 should be intuitive to anyone already familiar with how it is used for
76 The C<curries> functionality provided by AttributeHelpers has been
77 generalized to apply to all cases of C<< handles => HASHREF >>, though
78 not every piece of functionality has been ported (currying with a
79 CODEREF is not supported).
81 =item C<empty> is now C<is_empty>, and means empty, not non-empty
83 Previously, the C<empty> method provided by Arrays and Hashes returned true if
84 the attribute was B<not> empty (no elements). Now it returns true if the
85 attribute B<is> empty. It was also renamed to C<is_empty>, to reflect this.
87 =item C<find> was renamed to C<first>, and C<first> and C<last> were removed
89 L<List::Util> refers to the functionality that we used to provide under C<find>
90 as L<first|List::Util/first>, so that will likely be more familiar (and will
91 fit in better if we decide to add more List::Util functions). C<first> and
92 C<last> were removed, since their functionality is easily duplicated with
95 =item Helpers that take a coderef of one argument now use C<$_>
97 Subroutines passed as the first argument to C<first>, C<map>, and C<grep> now
98 receive their argument in C<$_> rather than as a parameter to the subroutine.
99 Helpers that take a coderef of two or more arguments remain using the argument
100 list (there are technical limitations to using C<$a> and C<$b> like C<sort>
103 See L<Moose::Meta::Attribute::Native> for the new documentation.
107 The C<alias> and C<excludes> role parameters have been renamed to C<-alias>
108 and C<-excludes>. The old names still work, but new code should use the new
109 names, and eventually the old ones will be deprecated and removed.
113 C<< use Moose -metaclass => 'Foo' >> now does alias resolution, just like
114 C<-traits> (and the C<metaclass> and C<traits> options to C<has>).
116 Added two functions C<meta_class_alias> and C<meta_attribute_alias> to
117 L<Moose::Util>, to simplify aliasing metaclasses and metatraits. This is
118 a wrapper around the old
120 package Moose::Meta::Class::Custom::Trait::FooTrait;
121 sub register_implementation { 'My::Meta::Trait' }
127 When an attribute generates I<no> accessors, we now warn. This is to help
128 users who forget the C<is> option. If you really do not want any accessors,
129 you can use C<< is => 'bare' >>. You can maintain back compat with older
130 versions of Moose by using something like:
132 ($Moose::VERSION >= 0.84 ? is => 'bare' : ())
134 When an accessor overwrites an existing method, we now warn. To work around
135 this warning (if you really must have this behavior), you can explicitly
136 remove the method before creating it as an accessor:
140 __PACKAGE__->meta->remove_method('foo');
146 When an unknown option is passed to C<has>, we now warn. You can silence
147 the warning by fixing your code. :)
149 The C<Role> type has been deprecated. On its own, it was useless,
150 since it just checked C<< $object->can('does') >>. If you were using
151 it as a parent type, just call C<role_type('Role::Name')> to create an
152 appropriate type instead.
156 C<use Moose::Exporter;> now imports C<strict> and C<warnings> into packages
161 C<DEMOLISHALL> and C<DEMOLISH> now receive an argument indicating whether or
162 not we are in global destruction.
166 Type constraints no longer run coercions for a value that already matches the
167 constraint. This may affect some (arguably buggy) edge case coercions that
168 rely on side effects in the C<via> clause.
172 L<Moose::Exporter> now accepts the C<-metaclass> option for easily
173 overriding the metaclass (without L<metaclass>). This works for classes
178 Added a C<duck_type> sugar function to L<Moose::Util::TypeConstraints>
179 to make integration with non-Moose classes easier. It simply checks if
180 C<< $obj->can() >> a list of methods.
182 A number of methods (mostly inherited from L<Class::MOP>) have been
183 renamed with a leading underscore to indicate their internal-ness. The
184 old method names will still work for a while, but will warn that the
185 method has been renamed. In a few cases, the method will be removed
186 entirely in the future. This may affect MooseX authors who were using
191 Calling C<subtype> with a name as the only argument now throws an
192 exception. If you want an anonymous subtype do:
194 my $subtype = subtype as 'Foo';
196 This is related to the changes in version 0.71_01.
198 The C<is_needed> method in L<Moose::Meta::Method::Destructor> is now
199 only usable as a class method. Previously, it worked as a class or
200 object method, with a different internal implementation for each
203 The internals of making a class immutable changed a lot in Class::MOP
204 0.78_02, and Moose's internals have changed along with it. The
205 external C<< $metaclass->make_immutable >> method still works the same
210 A mutable class accepted C<< Foo->new(undef) >> without complaint,
211 while an immutable class would blow up with an unhelpful error. Now,
212 in both cases we throw a helpful error instead.
214 This "feature" was originally added to allow for cases such as this:
222 return My::Class->new($args);
224 But we decided this is a bad idea and a little too magical, because it
225 can easily mask real errors.
227 =head1 Version 0.71_01
229 Calling C<type> or C<subtype> without the sugar helpers (C<as>,
230 C<where>, C<message>) is now deprecated.
232 As a side effect, this meant we ended up using Perl prototypes on
233 C<as>, and code like this will no longer work:
235 use Moose::Util::TypeConstraints;
236 use Declare::Constraints::Simple -All;
238 subtype 'ArrayOfInts'
240 => IsArrayRef(IsInt);
242 Instead it must be changed to this:
247 where => IsArrayRef(IsInt)
251 If you want to maintain backwards compat with older versions of Moose,
252 you must explicitly test Moose's C<VERSION>:
254 if ( Moose->VERSION < 0.71_01 ) {
255 subtype 'ArrayOfInts'
257 => IsArrayRef(IsInt);
263 where => IsArrayRef(IsInt)
270 We no longer pass the meta-attribute object as a final argument to
271 triggers. This actually changed for inlined code a while back, but the
272 non-inlined version and the docs were still out of date.
274 If by some chance you actually used this feature, the workaround is
275 simple. You fetch the attribute object from out of the C<$self>
276 that is passed as the first argument to trigger, like so:
282 my ( $self, $value ) = @_;
283 my $attr = $self->meta->find_attribute_by_name('foo');
291 If you created a subtype and passed a parent that Moose didn't know
292 about, it simply ignored the parent. Now it automatically creates the
293 parent as a class type. This may not be what you want, but is less
296 You could declare a name with subtype such as "Foo!Bar". Moose would
297 accept this allowed, but if you used it in a parameterized type such
298 as "ArrayRef[Foo!Bar]" it wouldn't work. We now do some vetting on
299 names created via the sugar functions, so that they can only contain
300 alphanumerics, ":", and ".".
304 Methods created via an attribute can now fulfill a C<requires>
305 declaration for a role. Honestly we don't know why Stevan didn't make
306 this work originally, he was just insane or something.
308 Stack traces from inlined code will now report the line and file as
309 being in your class, as opposed to in Moose guts.
311 =head1 Version 0.62_02
313 When a class does not provide all of a role's required methods, the
314 error thrown now mentions all of the missing methods, as opposed to
315 just the first missing method.
317 Moose will no longer inline a constructor for your class unless it
318 inherits its constructor from Moose::Object, and will warn when it
319 doesn't inline. If you want to force inlining anyway, pass
320 C<< replace_constructor => 1 >> to C<make_immutable>.
322 If you want to get rid of the warning, pass C<< inline_constructor =>
327 Removed the (deprecated) C<make_immutable> keyword.
329 Removing an attribute from a class now also removes delegation
330 (C<handles>) methods installed for that attribute. This is correct
331 behavior, but if you were wrongly relying on it you might get bit.
335 Roles now add methods by calling C<add_method>, not
336 C<alias_method>. They make sure to always provide a method object,
337 which will be cloned internally. This means that it is now possible to
338 track the source of a method provided by a role, and even follow its
339 history through intermediate roles. This means that methods added by
340 a role now show up when looking at a class's method list/map.
342 Parameter and Union args are now sorted, this makes Int|Str the same
343 constraint as Str|Int. Also, incoming type constraint strings are
344 normalized to remove all whitespace differences. This is mostly for
345 internals and should not affect outside code.
347 L<Moose::Exporter> will no longer remove a subroutine that the
348 exporting package re-exports. Moose re-exports the Carp::confess
349 function, among others. The reasoning is that we cannot know whether
350 you have also explicitly imported those functions for your own use, so
351 we err on the safe side and always keep them.
355 C<Moose::init_meta> should now be called as a method.
357 New modules for extension writers, L<Moose::Exporter> and
358 L<Moose::Util::MetaRole>.
360 =head1 Version 0.55_01
362 Implemented metaclass traits (and wrote a recipe for it):
364 use Moose -traits => 'Foo'
366 This should make writing small Moose extensions a little
371 Fixed C<coerce> to accept anon types just like C<subtype> can.
374 coerce $some_anon_type => from 'Str' => via { ... };
378 Added C<BUILDARGS>, a new step in C<< Moose::Object->new() >>.
382 Fixed how the C<< is => (ro|rw) >> works with custom defined
383 C<reader>, C<writer> and C<accessor> options. See the below table for
386 is => ro, writer => _foo # turns into (reader => foo, writer => _foo)
387 is => rw, writer => _foo # turns into (reader => foo, writer => _foo)
388 is => rw, accessor => _foo # turns into (accessor => _foo)
389 is => ro, accessor => _foo # error, accesor is rw
393 The C<before/around/after> method modifiers now support regexp
394 matching of method names. NOTE: this only works for classes, it is
395 currently not supported in roles, but, ... patches welcome.
397 The C<has> keyword for roles now accepts the same array ref form that
398 L<Moose>.pm does for classes.
400 A trigger on a read-only attribute is no longer an error, as it's
401 useful to trigger off of the constructor.
403 Subtypes of parameterizable types now are parameterizable types
408 Fixed issue where C<DEMOLISHALL> was eating the value in C<$@>, and so
409 not working correctly. It still kind of eats them, but so does vanilla
414 Inherited attributes may now be extended without restriction on the
415 type ('isa', 'does').
417 The entire set of Moose::Meta::TypeConstraint::* classes were
418 refactored in this release. If you were relying on their internals you
419 should test your code carefully.
423 Documenting the use of '+name' with attributes that come from recently
424 composed roles. It makes sense, people are using it, and so why not
425 just officially support it.
427 The C<< Moose::Meta::Class->create >> method now supports roles.
429 It is now possible to make anonymous enum types by passing C<enum> an
430 array reference instead of the C<< enum $name => @values >>.
434 Added the C<make_immutable> keyword as a shortcut to calling
435 C<make_immutable> on the meta object. This eventually got removed!
437 Made C<< init_arg => undef >> work in Moose. This means "do not accept
438 a constructor parameter for this attribute".
440 Type errors now use the provided message. Prior to this release they
445 Moose is now a postmodern object system :)
447 The Role system was completely refactored. It is 100% backwards
448 compat, but the internals were totally changed. If you relied on the
449 internals then you are advised to test carefully.
451 Added method exclusion and aliasing for Roles in this release.
453 Added the L<Moose::Util::TypeConstraints::OptimizedConstraints>
456 Passing a list of values to an accessor (which is only expecting one
457 value) used to be silently ignored, now it throws an error.
461 Added parameterized types and did a pretty heavy refactoring of the
462 type constraint system.
464 Better framework extendability and better support for "making your own
467 =head1 Version 0.25 or before
469 Honestly, you shouldn't be using versions of Moose that are this old,
470 so many bug fixes and speed improvements have been made you would be
471 crazy to not upgrade.
473 Also, I am tired of going through the Changelog so I am stopping here,
474 if anyone would like to continue this please feel free.
478 Stevan Little E<lt>stevan@iinteractive.comE<gt>
480 =head1 COPYRIGHT AND LICENSE
482 Copyright 2009 by Infinity Interactive, Inc.
484 L<http://www.iinteractive.com>
486 This library is free software; you can redistribute it and/or modify
487 it under the same terms as Perl itself.